1. Field of the Invention
The present invention relates to a compressed data scrambled distribution device and a playback device controlled by a digital watermark thereof.
2. Description of the Related Art
Conventionally, methods for carrying out descrambling by use of digital watermark as key information have been proposed in the following Patent Documents 1 and 2, for example.
Patent Document 1 discloses a method for generating a locking key by use of separately sent copyright information, player-specific information, and digital watermark information and carrying out descrambling based thereon. In addition, Patent Document 2 discloses a method for applying descrambling to data when a trigger signal embedded in the form of a digital watermark exists and outputting without descrambling when the trigger signal does not exist.
[Patent Document 1] Japanese Published Unexamined Patent Application No. 2001-78007
[Patent Document 2] Japanese Published Unexamined Patent Application No. 2002-534016
However, in both of the techniques, only one scramble signal is used, and there is no assumption that a plurality of types of scramble signals are selectively used.